Progressive Dual-Shaft Drill Head and Systems and Methods Thereof

ABSTRACT

Implementations of the present invention relate to system and apparatus for increasing and lowering speed and torque transferred to a drive shaft from a drive source. In particular, the present disclosure relates to a system that allows engagement and disengagement of low and high gears with a single shifter that can move in a single direction to shift between gears.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to U.S. Provisional Patent Application Ser. No. 61/585,576, filed on Jan. 11, 2012, the entire disclosure of which is hereby incorporated by reference.

BACKGROUND

1. Field of the Invention

Aspects described herein relate generally to drill heads and relate more specifically to systems, methods, and apparatus for changing the gear ratio of a drill head.

2. Related Art

Drill rigs generally include an upstanding mast with a mounted drill head. The drill head can be capable of moving along the mast. Additionally, the drill head can receive and engage the upper end of a drill string. The drill head can rotate the drill string and a drill bit mounted to the drill string to drill a formation. The drill string can include a plurality of drill rods that are connected end to end.

During a typical drilling operation, when the drill head reaches the lower end of the mast, the drill string can be clamped and the drill head disconnected from the drill string. An additional length of drill rod can then be added to the end of the drill string, the drill head connected to the new rod, and the drilling process resumed once again. During a drilling operation, depending on the depth of the borehole, numerous drill rods can be added to the drill string in order to reach a desired depth.

Depending on the type of the drilling operation, an operator of the drill rig can choose a particular speed of rotation for the drill head and, consequently, for the drill string. Changing the speed of rotation can typically be accomplished by shifting gears or splines in a gearbox, and/or modulating flow of hydraulic fluid to the motor, which transmits the rotational motion from a drive source to the drill string. For instance, by engaging a small gear, a highest number of revolutions per minute can be achieved (i.e., a higher speed). By contrast, by engaging a larger gear, a lower speed can be achieved and transferred to the drill string.

Ordinarily, to shift from the low gear into the high gear, an operator has to disengage the gears in the low gear and engage the gears in the high gear. As such, the operator can have to perform the above sequence in two separate steps and using two separate shifter levers. Use of a two-step shifting can cause unwanted delay in the drilling operation and, in some instances, can result in damage to the gears and/or gear box due to improper engagement and/or disengagement of the gears due to, for example, operator error.

Accordingly, a need exists for improved drill heads capable of shifting gears that reduces the risk of damage to the gears and/or gear box.

SUMMARY

It is to be understood that this summary is not an extensive overview of the disclosure. This summary is exemplary and not restrictive, and it is intended to neither identify key or critical elements of the disclosure nor delineate the scope thereof. The sole purpose of this summary is to explain and exemplify certain concepts of the disclosure as an introduction to the following complete and extensive detailed description.

Stated generally, the present disclosure comprises apparatus, systems and methods for shifting gears of a drill head.

Stated more specifically, the present disclosure comprises an apparatus and system that can allow engagement and disengagement of low and high gears with a single shift movement, which can improve mechanical robustness for deep-hole drilling applications. A single shift movement can eliminate or reduce the possibility of improper disengagement and/or engagement of the gears. Furthermore, in one or more aspects, at least one of a drill head and a gearbox can be further configured to provide for an automated shifting process. As such, gears can be shifted remotely, thereby further reducing the possibility of operator error and potential damage to equipment. Additionally, the system can be configured for higher torque output, can have various mounting arrangements, and can be configured for drilling in upward orientation.

Additional features and advantages of exemplary aspects of the disclosure will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by the practice of such exemplary aspects. The features and advantages of such aspects may be realized and obtained by means of the instruments and combinations particularly pointed out in the appended claims. These and other features will become more fully apparent from the following description and appended claims, or may be learned by the practice of such exemplary aspects as set forth hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate aspects and together with the description, serve to explain the principles of the methods and systems.

FIG. 1 illustrates a perspective view of a drill head in accordance with one aspect of the present invention.

FIG. 2A illustrates a cross-sectional view of the drill head of FIG. 1 in high gear in accordance with one aspect of the present disclosure.

FIG. 2B illustrates a transparent perspective view of a drill head of FIG. 2A.

FIG. 3A illustrates a cross-sectional view of a drill head of FIG. 1 in neutral gear.

FIG. 3B illustrates a transparent perspective view of a gearbox of FIG. 3A.

FIG. 4A illustrates across-sectional view of the drill head of FIG. 1 in low gear.

FIG. 4B illustrates a transparent perspective view of a gearbox of FIG. 4A.

FIG. 5 illustrates a perspective view of a shifter fork in accordance with one aspect of the present disclosure.

DETAILED DESCRIPTION

The present invention can be understood more readily by reference to the following detailed description, examples, drawing, and claims, and their previous and following description. However, before the present devices, systems, and/or methods are disclosed and described, it is to be understood that this invention is not limited to the specific devices, systems, and/or methods disclosed unless otherwise specified, as such can, of course, vary. It is also to be understood that the terminology used herein is for the purpose of describing particular aspects only and is not intended to be limiting.

The following description of the invention provided as an enabling teaching of the invention in its best, currently known aspect. To this end, those skilled in the relevant art will recognize and appreciate that many changes can be made to the various aspects of the invention described herein, while still obtaining the beneficial results described herein. It will also be apparent that some of the desired benefits described herein can be obtained by selecting some of the features described herein without utilizing other features. Accordingly, those who work in the art will recognize that many modifications and adaptations to the present invention are possible and can even be desirable in certain circumstances and are a part described herein. Thus, the following description is provided as illustrative of the principles described herein and not in limitation thereof.

Reference will be made to the drawings to describe various aspects of one or more aspects of the invention. It is to be understood that the drawings are diagrammatic and schematic representations of one or more aspects, and are not limiting of the present disclosure. Moreover, while various drawings are provided at a scale that is considered functional for one or more aspects, the drawings are not necessarily drawn to scale for all contemplated aspects. The drawings thus represent an exemplary scale, but no inference should be drawn from the drawings as to any required scale.

In the following description, numerous specific details are set forth in order to provide a thorough understanding described herein. It will be obvious, however, to one skilled in the art that the present disclosure may be practiced without these specific details. In other instances, well known aspects of drill string technology and, more particularly, shifting gears of a drill head have not been described in particular detail in order to avoid unnecessarily obscuring aspects of the disclosed aspects.

As used in the specification and the appended claims, the singular forms “a,” “an” and “the” include plural referents unless the context clearly dictates otherwise. Ranges may be expressed herein as from “about” one particular value, and/or to “about” another particular value. When such a range is expressed, another aspect includes from the one particular value and/or to the other particular value. Similarly, when values are expressed as approximations, by use of the antecedent “about,” it will be understood that the particular value forms another aspect. It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint, and independently of the other endpoint.

“Optional” or “optionally” means that the subsequently described event or circumstance may or may not occur, and that the description includes instances where said event or circumstance occurs and instances where it does not.

Throughout the description and claims of this specification, the word “comprise” and variations of the word, such as “comprising” and “comprises,” means “including but not limited to,” and is not intended to exclude, for example, other additives, components, integers or steps. “Exemplary” means “an example of” and is not intended to convey an indication of a preferred or ideal aspect. “Such as” is not used in a restrictive sense, but for explanatory purposes.

Aspects of the present disclosure provide systems, methods, and apparatus for shifting gears of a drill head. In particular, the present disclosure relates to a system that can allow engagement and disengagement of low and high gears with a single shift movement, which can improve mechanical robustness for deep-hole drilling applications. A single shift movement can eliminate or reduce the possibility of improper disengagement and/or engagement of the gears. Furthermore, in or more aspects, at least one of a drill head and a gearbox can be configured to provide for automation of the shifting process. One skilled in the art can appreciate that a drill head and/or gearbox configured for automated shifting can enable an operator to shift gears remotely, thereby further reducing the possibility of operator error and potential damage to equipment. Additionally, the system can be configured for a range of different torque output, can have various mounting arrangements, and can be configured for drilling in an upward orientation.

At least one aspect of the present disclosure can comprise a power transmission system configured to shift gears via a single linear or axial motion of an actuator. Such a system can simplify shifting between gears and, consequently, can reduce likelihood of human error or machine failure associated with shifting between gears. Moreover, such a system also have a reduced size as compared with conventional gearboxes used on drill heads. Size reduction can increase versatility and operability of the drill head that employs such a system.

The power transmission system can also comprise a manual or automated shifting mechanism. In particular, the single shift or single motion gear change can comprise an improved mechanism for incorporating an automated shifting mechanism. Accordingly, the automated shifting mechanism can result in improved reliability thereof. Similarly, the single motion gear change within the power transmission system can lead to improved reliability of the system.

Referring now to the drawings, in which identical numbers indicate identical elements throughout the various views, FIG. 1 illustrates a first aspect of a drill head 100 comprising a power transmission system 110, a drive shaft 120, and a drive source 130. In one aspect, the power transmission system 110 can operatively connect to the drive shaft 120 such that the power transmission system 110 can transmit rotation from the drive source 130 to the drive shaft 120. In a further aspect, the power transmission system 110 can be configured operate at various speeds, and can allow an operator to adjust the rotation transferred to the drive shaft 120. For instance, the power transmission system 110 can have a high gear and a low gear, where the high gear can transfer higher rate of rotational speed to the drive shaft 120 than the low gear.

In other aspects, the power transmission system 110 can comprise a gearbox 140 and a gear shifting system (not shown). The gear shifting system can cause a change in gear selection within the gearbox 140—i.e., the gear shifting system can cause the gearbox 140 to shift into a low gear thereby converting the input RPM to a lower output RPM (and higher torque). In operation and as described above, the gear shifting system can actuate the change from the low gear to the high gear, and vice versa, in a single motion.

The power transmission system 110 can comprise at least one input end and at least one output end. At least one drive source 130 (e.g., hydraulic or electric motors) can input rotational movement into the power transmission system 110 at an input RPM. The power transmission system 110 can convert the input RPM into an output RPM that the power transmission system 110 can output at the one or more output ends.

To transmit power (and rotation) from the drive source 130 to the drive shaft 120, the gearbox 140 can be operatively coupled to the drive shaft 120. At the input end, the drive source 130 can couple to a top portion of the gearbox 140 through a drive source adapter 132. At the output end, as illustrated in FIGS. 2A and 2B, the gearbox 140 can have an output gear 150 that can be operatively coupled to and drive an input gear 160 of the drive shaft 120. Alternatively, the output gear 150 can be operatively coupled to a freely spinning gear 170 that, in turn, can mesh the input gear 160. One skilled in the art can appreciate that, for example and without limitation, a chain-sprocket, belt-pulley, and the like as well as combinations thereof can be used for transmitting power from the output of the gearbox 140 to the input of the drive shaft 120.

The gearbox 140 and/or the drive shaft 120 can further comprise an enclosure or housing. For example the gearbox 140 can have a housing 180 configured to house various components of the gearbox 140. The housing 180 can protect the moving elements of the gearbox 140 from the surrounding environment and can also protect the operator from injury by the moving elements of the gearbox 140. Similarly, the drive shaft 120 can have a housing 190 operable to house the internal elements of the drive shaft 120 and protect such elements from the surrounding environment as well as the operator from injury by the moving elements within the drive shaft 120.

In one or more aspects, the gearbox 140 comprises a first hollow shaft 200 and a second hollow shaft 210. The first and second hollow shafts 200, 210 can be configured to rotate independently and freely if not engaged. The first and second hollow shafts 200, 210 can also be configured to rotate in unison, if coupled by an upper coupler or collar 220, as further described below.

In another aspect, bearings 230 a and 230 b (e.g., ball bearings, tapered bearing, journal bearings, etc.) can be rotatably secured the first hollow shaft 200 to the housing 180 to accommodate rotation. Similarly, bearings 230 c and 230 d can be rotatably secured the second hollow shaft 210 within the housing 180. The housing 180 can secure the bearings 230 a, 230 b, 230 c, 230 d with, for example and without limitation, clamps, channels, gibs, and the like. Alternatively, the housing 180 can further comprise integrated bearings 230 a, 230 b, 230 c, 230 d, such as, for example and without limitation, integrated journal bearings, outer rings of a ball bearing and the like. Furthermore, in other aspects, a single bearing can be used to restrain the first hollow shaft 200 and a single bearing to restrain second hollow shaft 210. In any event, the first and second hollow shafts 200, 210 can be restrained from axial (or lateral) movement with respect to the housing and permitted to rotate within the housing 180.

The first hollow shaft 200 can have the output gear 150 secured thereto. In one aspect, the output gear 150 can be secured to the first hollow shaft 200 such that the output gear 150 can be fixed and can rotate only together with the first hollow shaft 200. Alternatively, the output gear 150 can connect to the first hollow shaft 200 in a manner that can allow the output gear 150 and the first hollow shaft 200 to rotate independently of one another in the event a predetermined amount of torque is applied to the connection therebetween. In one aspect, a torque limiter can be installed between the output gear 150 and first hollow shaft 200, which can prevent damage to the output gear 150 and/or to the first hollow shaft 200 from excessive torque.

A drive rod 240 can be configured to engage the first hollow shaft 200 and transfer rotation from the drive source 130 to the first hollow shaft 200. In one aspect, the first hollow shaft 200 can also have an internal spline section 202 that can be configured to engage a corresponding section of the external spline on the drive rod 240. In another aspect, the drive rod 240 can have an external spline section that can engage an internal spline of the drive source 130. In an alternative or additional aspect, the drive rod 240 can have an internal spline section that can engage an external spline of the drive source 130. Moreover, one skilled in the art can appreciate that other connections can be used that can allow the drive rod 240 to move axially with respect to the drive source 130 such as, for example and without limitation, mating square sections, mating teethed sections and the like.

In other aspects, the drive rod 240 can be configured to move axially with respect to the drive source 130. A lower-shift connector 250 can be configured to couple to the first hollow shaft 200 such that movement of the lower-shift connector 250 can result in corresponding axial movement of the drive rod 240 as further described below. In one aspect, placing the lower-shift connector 250 into a first position can correspondingly place the drive rod 240 into a first position, as illustrated in FIGS. 2A and 2B.

The drive rod 240 can comprise multiple spline sections, which can be configured to engage mating splines of various elements within the gearbox 140. In a further aspect, the drive rod 240 can have at least one recessed regions separating the spline sections from adjacent spline sections. For example, the drive rod 240 can comprise a lower drive spline section 242 a that can be configured to engage a mating internal spline section 202 of the first hollow shaft 200. Here, when in the drive rod 240 is in the first position, the lower drive spline section 242 a can engage the internal spline section 202 of the first hollow shaft 200. In operation, when the drive rod 240 is in the first position, the drive rod 240 can be configured to transmit power (i.e., rotation) from the drive source 130 to the first hollow shaft 200, which can, in turn, transmit power to the drive shaft 120.

As described above, the gearbox 140 can comprise at least a high gear and a low gear. In other aspects, the gearbox 140 can be in high gear when the output end of the gearbox 140 is power powered directly by the drive source 130. Thus, when the drive rod 240 is in the first position, the gearbox 140 can be in high gear and can transfer power directly from the drive source 130 to the output end (e.g., the output gear 150) of the gearbox 140.

In another aspect, the drive rod 240 can further comprise one or more recesses that can abut or surround the spline sections. In one aspect, the drive rod 240 can have recesses 244 a, 244 b on both sides of the lower drive spline section 242 a. In this aspect, the drive rod 240 can move in an axial direction to disengage the lower drive spline section 242 a from the internal spline section 202 of the first hollow shaft 200. In operation, the lower-shift connector 250 can move the drive rod 240 in an axial direction such that the drive rod 240 is no longer coupled to the first hollow shaft 200.

In additional or alternative aspects, the lower-shift connector 250 can be configured to move the drive rod 240 to a second position, as illustrated in FIGS. 3A and 3B. In the second position, at least a portion of the recess 244 b of the drive rod 240 can approximately align with the internal spline section 202 of the first hollow shaft 200. Thus, in the second position, the drive rod 240 can be disengaged from the first hollow shaft 200, and no power (or rotation) can be transferred to the drive shaft 120 from the drive source 130. Accordingly, in the second position, the gearbox 140 can be in a neutral gear. When the gearbox 140 is in a neutral gear, the gearbox 140 can be configured to transfer no power or rotation from the drive source 130 to the output end of the gearbox 140.

In other aspects, the drive rod 240 can also be configured to engage a planetary gear system 260, which, in turn, can be configured to transmit power and rotation to the second hollow shaft 210. Here, the planetary gear system 260 can comprise a sun gear 262, one or more planet gears 264, and an outer ring 266. The planetary gear system 260 can further comprise a planet carrier 268, which can be configured to connect one or more planet gears 264 within the planetary gear system 260.

In certain aspects, the sun gear 262 can be configured to transmit motion to the planet gears 264. In operation, as the planet gears 264 rotate about the sun gear 262, the planet gears 264 can transmit motion to the outer ring 266 and/or to the planet carrier 268. For instance, if the outer ring 266 is fixed with respect to other components of the planetary gear system 260. (e.g., with respect to the sun gear 262 and planet gears 264), rotation of the sun gear 262 can transmit rotational motion to the planet carrier 268.

In other aspects, the planetary gear system 260 can be configured to act as a reducer and reduce the number of RPM from the drive source 130. In one aspect, the drive source 130 can transmit power to the sun gear 262 that can further transmit the power to the outer ring 266 or planet carrier 268, thereby reducing the RPM from the drive source 130. In an alternative aspect, the drive source 130 can couple to the outer ring 266 or planet carrier 268, thereby transmitting power through the outer ring 266 or planet carrier 268 to the sun gear 262, which can increase the output RPM.

In yet other aspects, the outer ring 266 can be configured to couple to or be incorporated into the housing 180 such that the outer ring 266 is stationary with respect to the drive source 130 and the drive rod 240. In one aspect, the drive rod 240 can couple to or engage the sun gear 262 and transmit power and rotation from the drive source 130 to the sun gear 262. Correspondingly, the sun gear 262 can also transmit power to the planet carrier 268 through the one or more planet gears 264. In operation, when the drive rod 240 couples to or engages the sun gear 262, the drive rod 240 and the sun gear 262 can transmit power and rotation from the drive source 130 to the planet carrier 268.

In other aspects, the planet carrier 268 can be coupled to the second hollow shaft 210. Thus, planet carrier 268 (and the planetary gear system 260) can be configured to transmit motion from the sun gear 262 onto the second hollow shaft 210. In operation, when the drive rod 240 engages the sun gear 262, the planetary gear system 260 can transmit power and rotational motion from the drive source 130 to the second hollow shaft 210.

In one or more aspects, the drive rod 240 can comprise an upper drive spline section 242 b that can mate with and engage an internal spline in the sun gear 262. When engaged with the sun gear 262, the drive rod 240 can be configured to transmit power and rotation from the drive source 130 to the sun gear 262. As described above, the lower-shift connector 250 can be configured to move the drive rod 240 axially. Accordingly, as illustrated in FIGS. 4A and 4B, the lower-shift connector 250 can move the drive rod 240 into a third position such that the upper drive spline section 242 b of the drive rod 240 engages the internal spline of the sun gear 262. In operation, in the third position, the drive rod 240 can transmit power and rotational motion from the drive source 130 through the planetary gear system 260 onto the second hollow shaft 210.

In other aspects, the internal spline sections of the first hollow shaft 200 and the sun gear 262 can comprise symmetrical or asymmetrical teeth that can be configured to correspond with external spline section of the drive rod 240. In one aspect, the spline sections can have teeth that have one angle on a first side of each tooth and a second, different angle on an opposite side. In an alternative aspect, the internal spline section 202 can have the same or substantially the same first and second angles on both sides of the teeth.

As described above, the first hollow shaft 200 and the second hollow shaft 210 can be configured to rotate independently when not engaged with each other. It is contemplated that, when the drive rod 240 engages the sun gear 262 of the planetary gear system 260 and, thereby, transmits power from the drive source 130 to the second hollow shaft 210, the first hollow shaft 200 can remain stationary unless engaged with the second hollow shaft 210. It is further contemplated that, when the first hollow shaft 200 remains stationary, the first hollow shaft 200 can not transmit power or rotation to the drive shaft 120.

In at least one aspect, the gearbox 140 can further comprise a separator bushing 270. In one aspect, the separator bushing 270 can be operable to separate the first hollow shaft 200 and second hollow shaft 210. In a further aspect, the separator bushing 270 can include a cylindrical portion that can fit into a hollow portion of the first or second hollow shaft 200, 210, and a flange that can separate ends of the first hollow shaft 200 and the second hollow shaft 210. In operation, the separator bushing 270 can act as a thrust bearing and/or can prevent the ends of the first hollow shaft 200 and second hollow shaft 210 from rubbing against each other, binding, and/or galling, when the first hollow shaft 200 or the second hollow shaft 210 rotate independently of one another.

In another aspect, the upper coupler 220 can be configured to engage the first hollow shaft 200 and the second hollow shaft 210 such that the second hollow shaft 210 can transmit rotation to the first hollow shaft 200 which can, in turn, transmit rotation to the drive shaft 120. In a further aspect, respective ends of the first hollow shaft 200 and second hollow shaft 210 can have external gears secured thereto or incorporated therewith. Here, the upper coupler 220 can have at least one internal gear that can mate with the external gears of the first hollow shaft 200 and second hollow shaft 210. In operation, when the upper coupler 220 engages the respective gears on the ends of the first hollow shaft 200 and second hollow shaft 210, the first hollow shaft 200 and second hollow shaft 210 can rotate in unison.

In light of this disclosure, one skilled in the art can appreciate other configurations for engaging the first hollow shaft 200 and second hollow shaft 210. For example and without limitation, the ends of the first hollow shaft 200 and second hollow shaft 210 can have a locking taper (e.g., a Morse taper) that can mate with a matching taper of the upper coupler 220 or the like. In a further aspect, the upper coupler 220 can also have internal and external portions that can move with respect to each other. Here, the internal portion can comprise of multiple floating leafs, made from a material with relatively high coefficient of friction on a surface that can come into contact with the ends of the first and second hollow shafts 200, 210. Also, the internal portion can have a taper on a surface that can come into contact with the external portion of the upper coupler 220. The external portion can be configured to have a matching taper, which can force the leafs of the internal portion against the ends of the first hollow shaft 200 and second hollow shaft 210, thereby coupling the first and second hollow shafts 200, 210. In yet further aspects, drive dogs can be used to mate the first hollow shaft 200 and second hollow shaft 210.

In other aspects of the present disclosure, the gearbox 140 can further comprise an upper-shift connector 280. The upper-shift connector 280 can be configured to engage the upper coupler 220 and move the upper coupler 220 such that the upper coupler 220 can couple and decouple the first hollow shaft 200 and the second hollow shaft 210. In operation, when moved to the first and/or second positions (illustrated in FIGS. 2A-2B and 3A-3B, respectively), the upper-shift connector 280 can move the upper coupler 220 toward the drive source 130, thereby disengaging the internal gear of the upper coupler 220 from the external gear on the end of the first hollow shaft 200 and/or external gear on the end of the second hollow shaft 210. When moved to the third position, illustrated in FIGS. 4A and 4B, the upper-shift connector 280 can move the upper coupler 220 away from the drive source 130, such that upper coupler 220 can couple the first hollow shaft 200 and the second hollow shaft 210.

In one or more aspects, the gearbox 140 can further comprise a link 151 (FIGS. 2B, 3B, 4B) configured to couple the lower-shift connector 250 and upper-shift connector 280, such that the lower and the upper-shift connectors 250, 280 can move in unison. In operation, as the lower-shift connector 250 and upper-shift connector 280 moves to the first position, the lower-shift connector 250 can urge the drive rod 240 to the first position and the upper-shift connector 280 can urge the upper coupler 220 to the first position. Similarly, when the lower-shift connector 250 and upper-shift connector 280 move to the second or third positions, the lower-shift connector 250 can urge the drive rod 240 to the second or third position and the upper-shift connector 280 can urge the upper coupler 220 to the second or third position, respectively.

Consequently, when moved into the first position, the lower-shift connector 250 and upper-shift connector 280 can shift the gearbox 140 into the high gear, as described above. In the second position, the lower-shift connector 250 and upper-shift connector 280 can shift the gearbox 140 into the neutral gear. And in the third position, the lower-shift connector 250 and upper-shift connector 280 can shift the gearbox 140 into the low gear. To shift between the first, second, and third positions, the lower-shift connector 250 and upper-shift connector 280 can be coupled to a gear shifting system.

In other aspects, shifting between the first, second, and third positions can occur while the drive rod 240, the first hollow shaft 200, and/or second hollow shaft 210 rotate within the gearbox 140. Thus, the upper coupler 220 can begin to engage and couple the first hollow shaft 200 and second hollow shaft 210 while the former and/or the latter rotate independently of one another. Similarly, the drive rod 240 can begin to engage the internal spline section 202 of the first hollow shaft 200 as well as the sun gear 262 of the planetary gear system 260 as the drive rod 240, first hollow shaft 200, and/or sun gear 262 rotate independently of one another. Moreover, the upper coupler 220 can be configured to engage and/or disengage the first and second hollow shafts 200, 210 independently of the drive rod 240 engaging and/or disengaging the sun gear 262 or the first hollow shaft 200. In operation, shifting between gears can occur irrespective of alignment between various moving components within the gearbox 140.

In one aspect illustrated in FIG. 5, the lower-shift connector 250 (and similarly the upper-shift connector 280) further comprises spring-loaded elements 290. When the lower-shift connector 250 and the upper-shift connector 280 are coupled by the link, the spring-loaded elements 290 can allow the lower-shift connector 250 and upper-shift connector 280 to move independently of each other while applying pressure in a direction of movement. As such, the spring-loaded elements 290 can operate to permit shifting between gears while various elements of the gearbox 140 rotate independently of one another. In operation, the gear shifting system can move the lower-shift connector 250 and/or upper-shift connector 280 into the first, second, and/or third position while the first hollow shaft 200, second hollow shaft 210, upper coupler 220, drive rod 240, and/or sun gear 262 (as applicable) are disengaged. Moreover, the spring-loaded elements 290 of the lower and upper-shift connectors 250, 280 can operate to limit the amount of force applied at engagement interfaces of the drive rod 240 and internal spline section 202 and the spline section of the sun gear 262 as well as at the engagement interface of the upper coupler 220 and the end of the first hollow shaft 200, which can improve reliability of the gearbox 140 and reduce wear and tear of the elements thereof.

In other aspects, when the lower and upper-shift connectors 250, 280 move from the second position to the third position, the lower-shift connector 250 can urge the drive rod 240 from the second position to the third position. In at least one aspect, the sun gear 262 can have rotational movement at an instance when the lower-shift connector 250 urges the upper drive spline section 242 b of the drive rod 240 into the internal spline of the sun gear 262. One skilled in the art can appreciate that the upper drive spline section 242 b can not immediately engage the spline of the sun gear 262. In another aspect, the spring-loaded elements 290 can allow the lower-shift connector 250 to deflect (as the gear shifting system shifts the lower-shift connector 250 into the third position) and apply force onto the drive rod 240 until the upper drive spline section 242 b of drive rod 240 aligns with and engages the spline of the sun gear 262. In another aspect, the spring-loaded elements 290 of the lower-shift connector 250 can be configured apply continuous force onto the drive rod 240 until the lower drive spline section 242 a engages the internal spline section 202 of the first hollow shaft 200 when the gear shifting system moves the lower-shift connector 250 into the first position.

In additional or alternative aspects, the spring-loaded elements of the upper shift connector 280 can apply continuous force onto the upper coupler 220 when the upper-shift connector 280 shifts to the third position, until the upper coupler 220 moves to the third position. In operation, the spring-loaded elements of the upper-shift connector 280 can press the upper coupler 220 against the gear on the end of the first hollow shaft 200 (while the first hollow shaft 200 rotates) until the gear of the upper coupler 220 aligns with and engages the gear on the end of the first hollow shaft 200. As described above, in the third position the upper coupler 220 can engage and/or couple the ends of the first hollow shaft 200 and second hollow shaft 210 such that the second hollow shaft 210 can transfer rotation to the first hollow shaft 200.

In yet other aspects, the first hollow shaft 200, the second hollow shaft 210, and the sun gear 262 can be configured to rotate independently. When the lower-shift connector 250 and upper-shift connector 280 move to the third position, the spring loaded elements can allow engagement of the first hollow shaft 200 (and coupling to the second hollow shaft 210) by the upper coupler 220 independent of the engagement of the drive rod 240 and the sun gear 262. In operation, the gearbox 140 can shift into the low gear by first engaging the drive rod 240 and the 262 of the planetary gear system 260, and subsequently, couple to the first and second hollow shafts 200, 210 by the upper coupler 220, or vice versa. The gearbox 140 can also shift into the low gear by, first, coupling the first and second hollow shafts 200, 210 with the aid of the upper coupler 220, and then engaging the drive rod 240 and the 262 of the planetary gear system 260.

Similarly, when the gearbox 140 shifts to the first position, the upper coupler 220 can be configured to disengage the end of the first hollow shaft 200 independently of the drive rod 240 disengaging the sun gear 262. Furthermore, while the spring-loaded elements can help engage the gears, in at least one aspect, the spring-loaded elements can be configured to not provide positioning during disengagement. Thus, the drill head can include positive disengagement and spring-loaded engagement.

In at least one aspect, the above-described components of the gearbox 140 can be configured to align in a substantially linear manner. Accordingly, the drive source 130, such as a hydraulic motor, can be configured to couple to a top portion of the gearbox 140. Such a configuration can allow a drive source 130 to be mounted at either or both ends of the gearbox 140. In an illustrative example, a hydraulic motor can be coupled to a bottom portion of the gearbox 140 (e.g., by coupling the hydraulic motor to a bottom portion of the drive rod 240). In additional or alternative aspects, two drive sources 130 can be coupled to the gearbox 140 (e.g., one to the top portion and another to the bottom portion of the gearbox)which can, individually or in parallel, power and rotate the drive rod 240.

In additional or alternative aspects, the gearbox 140 can be configured to shift from the first to the third position (and vice-versa) in a single or one-directional motion. One skilled in the art can appreciate that such automated gears shifting systems can be more reliable and durable than commercially-available alternatives. Furthermore, a manual gear shifting system embodying one-directional shifting can also improve reliability and durability of the gearbox 140 by reducing possibility of operator error.

In yet other aspects, the progressive dual shift design of the drill head 100 can allow the upper coupler or collar 220 and drive rod 240 to move at the same time. The shift connectors 250, 280 can be interconnected by a common shift linkage 151. Here, the top shift connector 280 can be configured to move the upper coupler or collar 220 and the lower shift connector 250 configured to move the drive rod 240. In operation, the shift connectors 250, 280 can be independently sprung to allow the shift to be completed regardless of spline engagement. The two shifts can be timed to allow the upper coupler or collar 220 to start to engage after the drive rod 240 shift is partially engaged.

In additional aspects, the lower shift shaft can comprise a lower fork split into two pieces configured to allow the two shift mechanisms to move independently against the springs. In further or alternative aspects, a special chisel tooth asymmetrical spline pointing can be provided to increase the aggressiveness of spline engagement during the shift. Furthermore, speed of rotation during spring loaded engagement can allow the engagement to occur without damage.

One skilled in the art can appreciate that, in light of the present disclosure, the drill head 100 can operate as a top drive or a spindle drive; can be shifted from high to low range manually or remotely from the driller's control station; can keep the drill operator away from the drill string; can be configured for a top or bottom mount motor; can be configured for higher or lower torque output; can be scaled up or down, can be configured for multiple mounting arrangements; can be configured to drill up holes; and can improve overall mechanical robustness for deeper hole applications.

Accordingly, FIGS. 1-5, and the corresponding text, provide a number of different components and mechanisms for apparatus and systems for changing the gear ratio of a drill head. In addition to the foregoing, implementations described herein can also be described in terms acts and steps in a method for accomplishing a particular result. For example, a method comprising engaging or disengaging gears associated with a drill head with a single shift movement is described concurrently above with reference to the components and diagrams of FIGS. 1 through 6.

Thus, implementations of the foregoing provide various desirable features. For instance, a one shift input shaft can allow the gearbox to be shifted with a single shift device (rather than two independent devices) such as, for example and without limitation, a hydraulic actuator, pneumatic actuator, manual actuated lever or the like. In another instance, one shift input can reduce or eliminate the possibility of operator error and resultant damage to the gearbox by having either shift mechanism in the wrong position when power is applied. Furthermore, one shift input can enable automation of the shifting process. The shift interconnecting linkage can be located inside the drill head to reduce damage during the drilling process and facilitate ease of installation on multiple drill rigs. Both upper and lower shift forks can be spring loaded to allow one or the other shift to occur independently if spline alignment of the other is not possible; allow the external shift actuator to achieve full stroke and lock with either spline disengaged; allow the shift to be automatically completed as the drive rod rotates with a spline disengaged and loaded against a spring; to limit the max force on the engaging splines reducing spline damage and limiting the load seen by the roll pins securing the shift forks to the shift shafts; and to reduce engagement time by snapping the splined component into place quickly as the splines rotate into position.

The present invention can thus be embodied in other specific forms without departing from its spirit or essential characteristics. The described aspects are to be considered in all respects only as illustrative and not restrictive. The scope of the invention is, therefore, indicated by the appended claims rather than by the foregoing description. All changes that come within the meaning and range of equivalency of the claims are to be embraced within their scope. 

What is claimed is:
 1. A drill head, comprising: at least one drive source; at least one drive shaft; and a power transmission system configured to transmit power from the at least one drive source to the at least one drive shaft and having at least a gearbox and a gear shifting system operatively coupled to the gearbox, wherein the gearbox further comprises: a drive rod operatively coupled to the at least one drive source, a first hollow shaft, a second hollow shaft and an upper coupler, and wherein: the drive rod is configured to move laterally to selectively couple directly to the first hollow shaft and to the second hollow shaft, the upper coupler is configured to move laterally to selectively couple the first and second hollow shafts, the first hollow shaft is operatively coupled to the at least one drive shaft, and the gear shifting system is operatively coupled to the gearbox to affect lateral movement of at least one of the drive rod and the upper coupler.
 2. The drill head of claim 1, wherein the power transmission system further comprises a reducer operable to couple the drive rod to the second hollow shaft.
 3. The drill head of claim 1, further comprising a housing, wherein at least a portion of one of the gearbox and drive shaft is enclosed in the housing.
 4. The drill head of claim 1, wherein the gearbox further comprises a drive source adapter operable to couple the drive source to the gearbox.
 5. The drill head of claim 1, wherein the gearbox further comprises an output gear operable to couple to the drive shaft.
 6. The drill head of claim 1, wherein the power transmission system has a high gear and a low gear, and wherein the high gear can transfer a higher rate of rotational speed to the at least drive shaft than the low gear.
 7. The drill head of claim 1, wherein the first and second hollow shafts are configured to rotate independently and freely if not coupled to the upper coupler.
 8. The drill head of claim 7, wherein the first and second hollow shafts are configured to rotate in unison when coupled to the upper coupler.
 9. The drill head of claim 1, wherein the drive rod is configured to engage the first hollow shaft and transfer rotation from the at least one drive source to the first hollow shaft.
 10. The drill head of claim 9, further comprising a planetary gear system configured to transmit power and rotation to the second hollow shaft, wherein the drive rod is configured to engage the planetary gear system.
 11. The drill head of claim 10, wherein the planetary gear system comprises a sun gear, one or more planet gears, an outer ring and a planet carrier, wherein the planet carrier is configured to connect the one or more planet gears within the planetary gear system.
 12. The drill head of claim 11, wherein the sun gear is configured to transmit motion to the planet gears.
 13. The drill head of claim 10, wherein the planetary gear system is configured to act as a reducer and reduce the number of RPM from the at least one drive source.
 14. A drill head comprising: a drive source; a drive rod connected to the drive source and operable to transmit rotation to the drive rod; a drive shaft; and a gearbox, comprising: a first hollow shaft operatively connected to the drive shaft such that rotation of the first hollow shaft is transmitted to the drive shaft, a second hollow shaft, a planetary gear comprising a sun gear secured to the second hollow shaft and at least one planet gear, wherein at least a portion of the planetary gear moves in response to rotation of the sun gear, and an upper coupler configured to engage the first and the second hollow shafts, such that rotation of the second hollow shaft is transmitted to the first hollow shaft; and wherein the drive rod is configured to selectively engage at least one of the at least one planetary gear and the first hollow shaft.
 15. The drill head of claim 14, wherein the planetary gear system further comprises an outer ring and a planet carrier, wherein the planet carrier is configured to connect the one or more planet gears within the planetary gear system.
 16. The drill head of claim 14, wherein the planetary gear system is configured to act as a reducer and reduce the number of RPM from the drive source.
 17. The drill head of claim 14, wherein the upper coupler is configured to move laterally to selectively couple the first and second hollow shafts.
 18. A drill head, comprising: a drive shaft operatively coupled to a transmission system, the transmission system comprising: a gearbox comprising: a first hollow shaft, a second hollow shaft, a planetary gear system having a sun gear and at least one planet gear, wherein a portion of the planetary gear system is configured to move in response to rotation of the sun gear is secured to the second hollow shaft, a drive rod configured to selectively engage at least one of the planetary gear and the first hollow shaft when moved laterally; and an upper coupler operable to couple the first and the second hollow shafts when moved laterally; and a gear shifting system operatively coupled to the gearbox and operable to cause lateral movement of at least one of the drive rod and the upper coupler.
 19. The drill head of claim 18, wherein the planetary gear system further comprises an outer ring and a planet carrier, wherein the planet carrier is configured to connect the one or more planet gears within the planetary gear system.
 20. The drill head of claim 18, wherein the planetary gear system is configured to act as a reducer and reduce the number of RPM from the drive source. 